When mounting a vessel that can be filled with a fluid or a cover such as a cylinder head cover or an oilpan made of metal or plastic, elastomeric seals are preferably used for sealing the individual components. The function of such a seal is not only separating the fluid from certain areas. In addition, such a seal should also bridge a gap which occurs between the components to be connected. Such a gap can be formed by inevitable production tolerances during the mounting process or by deformation as a result of thermal, mechanical or other influences during the use of a vessel, a cover or a trough.
When using fluid vessels it is inevitable that a sealing gap will occur between the components of such a fluid vessel to be connected, which gap reaches from the edge of the vessel to the seal and has a height of more than 0.1mm. This leads to the consequence that as a result of the capillary effect in the sealing gap a medium can penetrate the vessel from the outside. When such a sealing gap is inspected visually, the impression is given that the seal is perfect although the seal per se offers reliable sealing between the inside and outside space. Such an apparent tightness can hardly be distinguished from actual leakiness.
An additional problem can arise when a vessel filled with fluid is to be filled subsequently from the outside via a filling device or opening with the respective fluid. Depending on the position or the constructional configuration of this filling device or the opening it is inevitable that a residual quantity of the supplied fluid will reach the sealing gap during or after a filling process. Although the used seal will reliably seal the area from the inside of the vessel to the outside of the vessel, the impression might be given again due to the fluid present in the sealing gap that there is a leakage. Such an apparent leakiness leads to the consequence that efforts are made to remove the residual quantities of fluid from the sealing gap. This mostly occurs by complex and costly cleaning processes where it is acted upon the sealing gap from the outside. One example for such a cleaning process is cleaning by means of a high-pressure jet.
The problem of apparent leakiness can further occur when a vessel which is already filled with fluid and comprises components which are rigidly connected and sealed with each other is dismounted as a result of a maintenance measure. During such a dismounting process, residual quantities of the fluid reach a sealing groove and the adjacent outer flange area of the vessel. It is common practice that after the completed maintenance all components to be mounted again will be manually cleaned from residual quantities of the fluid. During the subsequent mounting of the components, these components are pressed tightly together with the seal, so that residual quantities of fluid are pressed out of the sealing groove. Despite a reliable sealing, the problem of apparent leakiness occurs again, so that laborious and mostly superfluous cleaning processes are performed.